Sylvinite ore is a mechanical mixture of sylvite (potassium chloride or “KCl”) and halite (sodium chloride or “NaCl”). Common sylvinite ores have about 31% KCl and 66% NaCl with the balance being extraneous materials, such as insoluble clays, anhydrite, and carnallite. Sylvinite ore is mined throughout North America. Sylvinite ore must be processed to remove the extraneous materials and separate the potassium chloride from the sodium chloride. The potassium chloride can thereafter be used in the production of potash and fertilizer.
There are various processes for separating potassium chloride from sylvinite. One of these is the flotation method. The flotation method involves the sorption of potassium chloride salts on a surfactant and the producing potassium chloride from solution. The flotation method, however, suffers from the drawback that only a very low degree of potassium chloride can be recovered from the sylvinite ore. Recovery of potassium chloride (KCl) from the ore is approximately 85%, and flotation tails, which goes to the waste takes 2.5-3% of potassium chloride.
Another method is the halurgic method. The halurgic method is based on the varying solubility of potassium chloride (KCI) and sodium chloride (NaCl) in water at different temperatures. KCI crystallizes out of a saturated solution upon cooling. The disadvantages of this method are the high energy costs involved and the low degree of potassium chloride recovery from the ore. Recovery of potassium chloride (KCI) from the ore is approximately 87.5%, and tails, which goes to the waste, takes 2.5-3% of potassium chloride.
Yet another method is disclosed in U.S. Pat. No. 2,762,505 to Lawyer. Lawyer illustrates an electrodynamic method for beneficiating sylvinite ore. The method recovers potassium chloride from potash-bearing ores. In one embodiment, dual electrostatic fields are used. Nonionizing fields with voltages varying between 1,000 to 5,000 volts or between 5,000 to 15,000 volts are disclosed.
RU 2,307,79 to Marakov et al. discloses a potassium chloride and sodium chloride production apparatus. Ground sylvinite ore is dissolved in recycled potassium chloride-saturated lye. The resulting solution is exposed to low-frequency (1-5 Hz) alternating electric fields at voltage source 30-100 v. A two column treatment method is also disclosed.
U.S. Pat. No. 3,073,447 to Autenrieth et al. discloses a system for electrostatic separation of potassium-containing materials. A conditioning agent is used prior to an electrostatic separator. Furthermore, U.S. Pat. No. 3,477,566 to Autenrieth et al. discloses a process for the electrostatic separation of the sylvite (KCI) component of a mineral. The process conditions particulate crude salt with inorganic mineral acids, inorganic alkaline reacting substances, and organic conditioning agents prior to electrostatic charging.
The background art also contains several examples of methods for processing carnallite ores. Like sylvinite ores, carnallite ores are a source of potash and fertilizer. Carnallite's chemical formula is KMgCl3.6(H2O). Naturally occurring carnallite is hard to find and typically occurs only in evaporating seas or sedimentary basins. For this reason, various efforts have been made over the years to produce artificial or synthetic carnallite. The background art contains various examples of producing synthetic carnallite from the crystallization of KCl and MgCl2.6H2O.
Artificial carnallite may be produced via known methods, such as the flotation and halurgic methods discussed above can also be used in the production of artificial carnallite. But again, these methods suffer from numerous disadvantages, including the low degree of the effective product recovery and the need for cumbersome technical procedures for ore processing.
Thus, there are inherent disadvantages found in the background art. These disadvantages include complexity of implementation due to the need for special equipment and the need for large production areas. There are also high energy and material costs associated with the background art. The systems of the background art also produce a low quality end product. The present disclosure is aimed at overcoming these and other shortcomings found in the background art.